Generally, when a customer selects fried chicken at a fried chicken shop, important factors considered by customers would be quality of chicken meat, taste and flavor of source, and costs, etc., in order. In particular, though there may be slightly different depending on regions, customers generally tent to prefer a particular brand. One of the reasons why the customers prefer a certain brand is a proper use of frying oil. For example, a particular brand can give to the customers a belief that the brand will use good frying oil of condition.
Meanwhile, though the quality of chicken meat and the source are used to advertise brand, they have been overused and wouldn't be of help to advertisement of brand. However, if the condition of frying oil used in each branch shop is notified to customers, the customers who want to have fresh food appreciate the brand of the branch shops.
Frying oil is generally oxidized and altered when a certain period of time is elapsed. For example, frying oil is rancid by heating, contact with air, light, or moisture. Once frying oil is rancid, burnt smell and smoke come out of the frying oil, bubbles occur when cooking food, and it becomes sticky and dark color.
As frying oil is used, heating temperature is high, and viscosity increases, smoke point is lowered. Smoke point is a temperature at which oil is burnt. If smoke point is lower, food is easy to burn, thereby downgrading the quality of fried food as well as becoming a cause of cancer in severe case.